Cheaper, cleaner, safer – these goals set a huge technological challenge for Australia’s energy sector in the coming quarter century.
The aim is to achieve secure energy in an insecure world, zero emissions in a greenhouse world, clean power in a green-conscious world and low-cost energy amid global price rises.
Hammering out the solutions is a team of the nation’s leading researchers in the Co-operative Research Centres and their partners in industry, universities and government.
On the positive side of the ledger are Australia's vast resources - from two to six centuries’ supply of brown and black coal and at least 60 years’ supply of natural gas.
These pluses are offset by Australia’s rising vulnerability to a liquid fuels crisis, slow growth in renewables and concern over global warming. Most analysts agree that, no matter how swift the uptake of renewables, fossil fuels will still be shouldering the national energy load in 2030.
But they will be doing so cleanly. The objective is to prove, and begin the transition to, low emission technologies within 5-7 years, near zero emission technologies in 15 years and a hydrogen economy in Australia in the longer term – without a hiccup in energy supply.
Black coal
Two new demonstration projects will cost upward of half a billion dollars, possibly the most expensive scientific experiments in Australia’s history but a necessary investment.
Researchers from CRC for Coal in Sustainable Development (CCSD) will support their partners planning to road-test the energy highways to the future: advanced technologies such as oxy-fuel combustion or gasification combined with the capture and storage of their carbon dioxide emissions.
Both are key planks in the COAL21 Action Plan and lead potentially to a hydrogen economy, according to Frank van Schagen, chief executive officer of the CCSD.
Oxy-fuel combustion involves burning coal with added oxygen. The technology potentially has two main advantages: combined with carbon dioxide capture and storage technology, it can reduce greenhouse emissions by 50 to almost 100% for a small penalty in efficiency. Secondly, if a more rapid response is required to greenhouse gas emissions it can be retro-fitted to existing power plants.
An Australian-Japanese consortium is undertaking an 18-month feasibility project to retrofit a boiler at the CSEnergy Callide A power station in Queensland with oxy-firing technology to test a range of local coals, and to take off the residual carbon dioxide in a stream pure enough to be safely stored underground through a process known as geo-sequestration.
Led by participants in CCSD, the partners include Japan’s IHI Engineering and the CRC for Greenhouse Gas Technology (CO2CRC).
“Significant technical improvements in oxygen production and capture technologies are pushing down the cost of oxy-fuel coal fired power plants,” van Schagen says.
“These advances should make the overall cost affordable for electricity users. If oxy-fuel technology is applied to modern supercritical plant you can potentially capture and store a large proportion of the emissions without serious loss in efficiency.”
Since the power industry produces 40% of Australia’s greenhouse gas output, such an improvement applied industry-wide could potentially cut national emissions by around one fifth – a huge contribution to national targets – while keeping coal highly competitive as a fuel. How close to zero emissions the technology could be taken depended largely on the economics, according to van Schagen.
Pilot and demonstration coal gasification projects are also being developed by other Queensland interests, to which CCSD will contribute its coal knowledge.
Demonstration of a 100-megawatt coal gasification (IGCC) plant will cost an estimated $350 million. Coupled with geo-sequestration, this technology offers potential gains in energy efficiency as well as close-to-zero greenhouse and other emissions.
The Japanese and Americans believe energy efficiencies as high as 50-60% are attainable with IGCC in the medium term. The US is aiming to have its first FutureGen IGCC plant on-line by 2011.
Gasification involves converting coal to synthesis gas (syngas), a mixture of hydrogen and carbon monoxide, which can either be burnt directly in turbines to produce electricity or else, reacted with steam to produce pure streams of hydrogen (for energy generation) and carbon dioxide (for sequestration).
While both technologies were being explored overseas, van Schagen said it was essential to make sure they work with Australian coals under Australian conditions.
Gasification also opens up another vital possibility – as insurance against a critical shortfall in Australian transport fuels as domestic oil supplies contract amid continuing political instability in the Middle East.
Coal and syngas can both be converted to a very clean liquid diesel fuel, and hydrogen is seen by commentators as the future transport mainstay in the longer term.
Brown coal
If Australia has centuries’ worth of black coal and natural gas still to exploit, it has an even greater bounty of brown coal, or lignite. Estimates range from 400-600 years’ supply in Victorian and South Australian beds alone.
Brown coal has been condemned as being polluting and inefficient, but a series of scientific advances are spectacularly improving its attractiveness, according to The Cooperative Research Centre for Clean Power from Lignite (CRC CPL).
Professor Julian Cribb FTSE is a science journalist and communicator.
Tomorrow - clean energy from dirty coal.
